Abstract
A new stabilographical method with pressure loading to the external auditory canal (PLT) was performed in 20 normal subjects and 3 patients with Meniere's disease for the purpose of testing the pseudofistular sign. The pressure ranging from -100mmH2O to +100mmH2O or from -200mmH20 to +200mmH2O were applied to the external auditory canal and the body sways of the center of gravity to the lateral directions for 10 seconds were summated 10 times by a signalprocessor (NEC-sanei, 7TO7A). Positive response was defined as having doubles sway amplitude compaired with the average amplitude of sway without pressure loading.
Positive response were observed in seven of twenty normal subjects. These positive reactions were symmetrical in both ears except one case. On the other hand, in cases of Meniere's disease, positive responses were found only in the affected ears. The positive PLT response was not changed at all when the test was repeated in a case of Meniere's disease at the stage of positive response to the grycerol test, however, in another case of Meniere's disease, disappearance of positive PLT response was observed after the puncture of the eardrum.
From these findings we considered that the most effective facter of the PLT in producing the deviation was not the pressure change of the middle ear, but the movement of the ossicular chain causing displacement of the foot-plate of stapes.
